The question
Are the fees incurred by phone owners to receive verification-codes sent as sms messages legal ?
When registering to make new email-accounts( etc ) those companies often send you a verification-code ( 2FA ) in an sms to confirm that you do actually own that phone-number, and receiving that sms often incurs some sort of fee / cost on your phone-account.
LINK - Multi-factor authentication ( MFA; two-factor authentication, or 2FA )
Quote from above link - "Mobile carriers may charge the user for messaging fees. "
Malicious people could do false account registrations using someone else s phone-number just in order to incur fees on them
What if some companies send these sms as self-deleting sms messages ( or invisible sms messages if there is such a thing ? ), then the receiver would not be able to work out what is eating their phone-credit ?
NOTE - I have not been able to find out if fees are only incurred if the verification-code is successfully used to sign-up for a new account ( or re-verify ID etc ).
I wonder if this question should be more general and cover any sms messages that incur a fee on the receiver.
NOTE - I just realized that I may have posted this question based on my incorrect assumption that verification-code sms-messages may be treated differently to normal sms-messages on a phone-account where normally the receipt of all sms-messages seems to be free, when in fact the phone-carriers would probably never be able to tell the difference between verification-code sms-messages and normal sms-messages.
( The text shown by email-account sign-up webpages like "Receipt of the verification-code sms-message may incur a charge." and also forgetting about countries where receivers pay for calls or sms, prompted me to post this question )